Report exit status in debug stub, if tab is closed in chrome.

src/trusted/service_runtime/nacl_secure_service.c

 /*
  * Copyright (c) 2012 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "native_client/src/trusted/service_runtime/nacl_secure_service.h"
 
 #include "native_client/src/shared/platform/nacl_exit.h"
 #include "native_client/src/shared/platform/nacl_log.h"
@@ skipping 82 matching lines @@
 static void NaClSecureServiceConnectionCountDecr(
     struct NaClSecureService *self) {
   NaClLog(5, "NaClSecureServiceThreadCountDecr\n");
   NaClXMutexLock(&self->mu);
   if (0 == self->conn_count) {
     NaClLog(LOG_FATAL,
             "NaClSecureServiceThreadCountDecr: "
             "decrementing thread count when count is zero\n");
   }
   if (0 == --self->conn_count) {
     NaClLog(4, "NaClSecureServiceThread: all channels closed, exiting.\n");

[bsy, 2012/10/23 17:42:35]

please add a comment for why this is needed, since w/o debug stub this isn't.

also, this function name suggests that it reports an exit status but will
return.  (which is indeed what it does.)  maybe add a comment that this will
cause the service runtime's main thread to exit as a side-effect?

i don't think we should use 0 here as the "exit status", since it conflates the
NaCl module's use of the exit syscall with value 0 with the command channel
closure, which is more akin to a kill or sigpipe.  we should probably encode it
in the wait status the same way that posix does with 8 bit exit status and
termsig/stopsig etc.

[halyavin, 2012/10/23 18:42:42]

I added a comment.
This is normal scenario in browser. So I don't think we need to send non-zero
here.
 
FYI, debug stub sends only 8 bits of exit code.

-    NaClExit(0);
+    NaClReportExitStatus(self->nap, 0);
   }
   NaClXMutexUnlock(&self->mu);
 }
 
 int NaClSecureServiceAcceptConnection(
     struct NaClSimpleService            *vself,
     struct NaClSimpleServiceConnection  **vconn) {
   struct NaClSecureService *self =
     (struct NaClSecureService *) vself;
   int status;
@@ skipping 215 matching lines @@
 
 struct NaClSecureReverseClientVtbl const kNaClSecureReverseClientVtbl = {
   {
     {
       NaClSecureReverseClientDtor,
     },
   },
   NaClSecureReverseClientInsertHandler,
   NaClSecureReverseClientRemoveHandler,
 };